Cartridge oil seal for rotating combustion engines

ABSTRACT

An oil seal for the rotor of a rotary piston engine wherein the seal assembly includes a cartridge having a housing member with an open axial end containing a sealing member axially movable in the housing and a spring member to urge the sealing member out of the open end, the housing being configured to retain the sealing member at the other end.

United States Patent Prasse et a1.

[ CARTRIDGE OIL SEAL FOR ROTATING COMBUSTION ENGINES [75] Inventors: Harold F. Prasse, Town and Country; Harold E. McCormick, Ballwin, both of Mo.

[73] Assignee: Ramsey Corporation, St. Louis, Mo.

[22] Filed: Oct. 1, 1971 211 Appl. No.: 185,581

[52] U.S. C1. 418/142, 267/15, 277/35 [51] Int. C1.... F0lc 19/00, F04c 15/00, F040 27/00 [58] Field of Search 418/142, 144; 277/157-161, 35-52; 267/158, 182, 1.5;

[56] References Cited 1 UNITED STATES PATENTS 1,439,845 12/1922 Seib et a1. 277/158 1,963,849 6/1934 Johnson 277/51 2,088,703 8/1937 Hubbard et a1 277/49 2,111,258 3/1938 Zahodiakin....' 267/15 2,3611 10 11/1944 Krug ..'277/38 2,434,484 1/1948 Chambers 277/49 July 9, 1974 2,593,899 4/1952 Krug 277/40 2,650,117 8/1953 Chambers et a1... 277/42 3,171,590 3/1965 Bentele et a1 418/142 3,300,127 1/1967 Yamamoto et a1. 418/142 3,400,939 9/1968 Jones 418/142 3,575,541 4/1971 Hamada 418/142 FOREIGN PATENTS OR APPLICATIONS 719,960 12/1954 Great Britain 277/38 176,401 10/1953 Austria 277/158 Primary ExaminerWi11iam L. Freeh Assistant Examiner-John J. Vrablik Attorney, Agent, or Firm-Hill, Gross, Simpson, Van Santen, Steadman, Chiara & Simpson ABSTRACT An oil seal for the rotor of a rotary piston engine wherein the seal assembly includes a Cartridge having a housing member with an open axia1 end containing a sealing member axially movable'in the housing and a spring member to urge the sealing member out of the open end, the housing being configured to retain the sealing member at the other end.

18 Claims, 8 Drawing Figures PATENIEDJUL swim 3.822.973

SHEEI 2 OF 2 5 7 INVENTORS e aim TTORNEYS flerber/ fP/"asse I 1 CARTRIDGE OIL SEAL FOR ROTATING COMBUSTION ENGINES BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to internal combustion engine sealing rings and more particularly to an oil seal for a rotary piston engine.

-2. Description of the Prior Art Rotary piston engines, and particularly those of the Wankel design, require sealing between the side walls of the rotor and the side walls or end plates of the rotor chamber. Because engines of the Wankel type have a central opening in the rotor which is lubricated, it is not only necessary to seal against escape of combustion gases from the outer diameter of the rotor towards the inner diameter, it is also necessary to seal against a flow of lubricant from the inner diameter of the rotor to the outer diameter or combustion area; It has been known to accomplish such sealing through the use of oil seal rings which have their axial end walls urged against the end plate and which are received in grooves in the rotor side wall. While such prior art oil seals do function to reduce oil flow from the inner diameter to the outer diameter of the rotor, they are not as effective as desirable, generally require a large number of parts, are dif' ficult to assemble into the rotor grooves and can fall out of the grooves during installation of the rotor in the engine.

BRIEF SUMMARY OF THE INVENTION Thisinvention improves upon the art by providing a cartridge-type seal. In this manner, although the seal unit may contain a number of parts, a single cartridge is provided for insertion into the side of the rotor. This minimizes difficulties of installation during assembly of the engine while at the same time providing a more effective seal design.

In the preferred embodiments illustrated illustrated, the cartridge assembly includes a housing member which is ring-shaped, the ring being of substantially U- shaped cross section with one axial end wall of the ring being open. The housing has positioned therein one or more seal rings which have an axial projection on one end walland a U-shaped cross section configuration with the projection extending from the bight of the U outwardly. A spring member is received within the U and is bottomed against the bight wall of the housing and against the inner bight wall of the seal member to urge the seal member away from the bight wall of the housing and out of the open end with the projection extending out from the housing. The side walls of the housing are bent inwardly at the open end to a clearance less than the radial width of the seal member to retain the seal member therein. The entire cartridge is then capable of being assembled into a ring groove in the side of the rotor and thespring will then urge the sealing member away from the back wall of the housing and into contact with the end plate of the rotor. chamber. Due to the retaining nature of the bent-in side walls, the seal components cannot fall out of the cartridge during assembly. Further, the cartridge itself, may be press fit in the rotor groove, thereby overcoming one of the difficulties of the prior art.

In one embodiment, the cartridge includes only one seal member with one expansion spring. In another embodiment a plurality of concentric seal members are provided with a plurality of expansion springs and secondary seals may be provided between the primary seals and the housing.

In a main embodiment, the axial end of the projection is blunt whereas in modification thereof, the axial end may be tapered.

It is therefore an object of this invention to provide an improved oil seal for rotary piston engines.

It is a further object of this innvention to provide an oil seal assembly for rotary combustion engines which allows the use of relatively wide ring grooves.

It is another and more particular object of this invention to provide an oil seal assembly for rotary piston engines wherein the seal assembly is preassembled into a cartridge for insertion into a ring groove as a unit.

It is a further and more specific object of this invention to provide a cartridge oil seal assembly for rotary piston engines with the cartridge including a housing member with an open axial end, a sealing member contained in the housing member and a spring member to urge the sealing member out of the open end of the housing with means to prevent the sealing member from totally leaving the housing.

It is another and more specific object of this invention to provide a cartridge oil seal assembly for rotary piston engines, the assembly including a U-shaped cross section housing ring having an open axial end,a pair of seal rings received in the housing having axial 3( sealing faces thereon, a pair of axial expansion members received in the housing urging the seal rings away from the back wall of the housing, the assembly being adapted to be received in a ring groove. O

Other objects, features and advantages of the present invention will be readily apparent from the following detailed description of certain preferred embodiments thereof taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary cross sectional view of the side of a rotary piston and the end plate of a chamber illustrating the cartridge seal assembly of this invention received in a ring groove in the piston;

FIG. 2 is a plan view of one of the seal rings of this invention;

FIG. 3 is a cross sectional view of the seal ring of FIG.

FIG. 4 is a plan view of the expander ring of this invention;

v FIG. 5 is a side view of the ring of FIG. 4 partially in section;

FIG. 6 is a view similar to FIG. 1 illustrating a modified form of the cartridge seal assembly of this invention;

FIG. 7 is a view similar to FIG. 1 illustrating another embodiment of the cartridge seal assembly of this invention; and

FIG. 8 is a view similar to FIG. 1 illustrating yet another embodiment of the cartridge seal assembly of this invention.

DESCRIPTION OF THE PREFERRED EMBODI- MENTS Many of the prior art oil control systems for use in rotary piston engines utilized one or more radially narrow oil control ringswhich were received in radially narrow, axially elongated grooves in the side of the rotor.

The grooves were generally concentric with the central opening of the rotor. Where two rings were used, two grooves were also required. Because of the difficulty of machining circular grooves in a flat face, it is desirable if the grooves can be made radially wide as compared to the prior art-rings which required radially narrow grooves. Further, because of the radial narrowness of the prior art grooves and because of the fact that a rotary piston engine oil ring assembly normally requires a plurality of parts, it was difficult to assemble the prior art. FIG. 1 illustrates an oil ring assembly which overcomes these disadvantages. The assembly is a cartridge containing components which can be preassembled. The cartridge itself is receivable in a radially wide groove 11 in the side wall 12 of the piston 13. The assembly includes means to urge seal ring members out of the open end 14 of the groove and into contact with the wall 15 of the end plate 16.

The seal assembly 10 then comprises a cartridge assembly 17 which is receivable in the groove 11. The cartridge includes a housing member 18, sealing members l9 and 20, biasing, spring members 21 and 22 and a static seal member 23.

The housing member 18 is a ring-shaped member having its radial thickness of U-shaped cross section providing a radially extending back wall or bight section 24, two axially extending concentric side walls 25 and 26 integral with the bight section at either end thereof. and an open axial end 27. The free ends 28 and 29 of the legs 25 and 26 are inturned at the open axial end 27 to reduce the opening at 27 to a radial dimension less than the interior radial dimension of the hous- The housing 18 is dimensioned radially and axially with respect to the groove 11 so that the housing is snugly fitted in the groove. If desired, this may be a press-fit relation which will retain the cartridge in the groove in a tight and sealing engagement with the side wall of the groove.

The axial depth of the housing with respect to the groove is such that the housing is preferably received entirely within the groove with the bight section 24 bottoming against the back wall 30 of the groove and the inturned ends 28 and 29 terminating interiorly of the groove at least flush with the groove opening or slightly interior thereof.

ln the embodiment illustrated in FIG. 1, two seal rings 19 and are provided. The rings are concentric and are of different diameters so that the ring 20 is received around the ring 19. The ring 19 preferably has an inner diameter slightly greater than the inner diameter of the housing so as to be movable therein without interference. The inner diameter of the ring 19, however, is less than the diameter of the inturned lip 29 so that when the ring is assembled into the housing and the lip 29 inturned, the ring is prevented from falling out of the housing. The outer ring 20 has an inner diameter slightly greater than the outer ring 19 so that it is receivable therearound without interference and movable independently of the ring 19 within the housing. The outer diameter of the ring 20 is slightly less than the inner diameter of the leg of the housing so that there is no interference between the leg 25 and the ring. However, the outer diameter of the ring 20 is greater than the diameter of the inturned lip 28 so as to prevent exit of the ring 20.

Each of the rings 19 and 20 has its radial thickness formed substantially in a U-shaped cross section shape with an inner diameter leg 31 and an outer diameter leg 32 which are interconnected at one axial end of the legs by a bight section 33 integral with the legs 31 and 32. The bight section 33 forms an axial end wall extending in a radial direction while each of the legs 31 and 32 forms a peripheral circumferential axially extending wall.

A sealing nose 35 projects axially from the outer surface of the bight section 33 intermediate the inner and outer diameters thereof.

The outer end surface 36 of the nose 35 forms a sealing face or scraping face for contacting the wall 15 of the end plate 16.

Positioned interiorly of each of the channels 37, which are formed between the legs 31, 32 and the bight section 33 and are open to the exterior at the open ends 34, is a spring member 21 or 22. The spring member provides an axial thrust to urge the seal members out of the open end 27 of the housing.

As illustrated in FIGS. 1, 4 and 5, each of the biasing, spring members 21, 22 preferably is a ring having its radial thickness of U-shaped cross section with inner diameter, axially extending, legs 40 and outer diameter, axially extending, legs 41, interconnected by a radially extending bight section 42 at one axial end of the legs 40 and 41, the other axial end open as at 43 giving access to a channel between the legs.

The bight section 42 has a plurality of seal ring biasing spring elements in the form of fingers 44 projecting therefrom. The spring fingers 44 are formed of circumferentially spaced alternately oppositely radially extending struck-out sections of the bight 42 and portions of the legs 40 and 41 with one axial end integral with the leg 40 or 41 and the other axial end projecting axially beyond the bight 42. The rings 21, 22 are preferably formed of spring metal whereby the fingers 44 are resilient and serve to axially urge the seal rings away from the bight section 42 of the spring rings.

The spring rings 21, 22 may be formed unitary or may be split.

The ring 21 is dimensioned to be received in generally nested relation interiorly of the channel 37 of the ring 19 and the ring 22 is dimensioned to be received in generally nested relation interiorly of the channel of the ring 20. The spring rings 21 and 22 have an axial length from the free axial ends of the spring fingers 44 to the opposite axial ends of the legs 40, 41 greater than the axial length of the channel of the rings 19 and 20. In this manner when the open end 43 of the spring rings is abutted against the bight 24 of the housing, the bight 42 will be in spaced proximity relation to the bight 33 and the spring fingers 44 will act as balanced biasing springs against the inner surface of the bight 33 of the sealing rings to urge them axially away from the housing bight 24 and out of the open end 27 of the housing.

In order to provide static sealing between the elements of the cartridge, interiorly of the cartridge, a quad ring 23 is inserted into the housing radially intermediate the outer diameter leg 41 of the inner spring ring 21 and the inner diameter leg 40 of the outer diameter spring ring 22. The quad ring is dimensioned to contact both of the spring rings and to contact the inner diameter faces of the outer diameter leg 32 of the sealing ring 19 and the inner diameter leg 31 of the sealing ring 20, as illustrated in FIG. 1. The quad ring 23 functions as a'secondary seal within the housing 18 of the seal assembly cartridge 17 while the seal rings 19 and 20 function as primary seals.

Further, in order to prevent oil leakage around the cartridge in the ring groove, a groove 50 may extend into the body of the piston 13 from the bottom wall of the ring groove 11. An O-ring 51 can be received in the groove 50. The O-ring bottoms against the outer face of the bight 24 of the housing as illustrated.

FIGS. 7 and 8 illustrate modifications of the embodiment of FIG. 1. In FIG. 7 the seal rings 49 and 50 corresponding to the rings 19 and 20 of FIG. 1 have the axial end faces 51 of the sealing noses 52 formed with a reverse bevel 53. In the embodiment illustrated in FIG. 7, the piston center is located in the direction of the arrow C. The taper extends away from the center towards the outer diameter of the rotor so that the high point of the taper is adjacent the inner diameter of the sealing nose 52. In this way the oil seal assembly is made inwardly pumping so as to aid in preventing leakage of oil towardthe outer diameter of the rotor.

FIG. 8 illustrates a further modification where the sealing nose 54 of the rings 55 and 56 is radially wider than in previous embodiments and extends for substantially the full length of the bights 57, 58 of the rings 55, 56, except for a portion adjacent the inner diameter of the inner ring 55 and adjacent the outer diameter of the outer ring 56 which have axial cutback sections 59 forming ledges. In this manner the ledgescan abut the inturned sides 28, 29 of the cartridge housing to prevent exit of the ring.

The sealing noses 54 have an axial dimension such that they will effectively contact the wall 15 of the side plate 16 before contact between the inturned ends 28, 29 of the side legs prevents further axial movement. In the embodiment illustrated in FIG. 8, the sealing noses again have a reverse taper to make them inwardly pumping.

FIG. 6 illustrates another modification of this invention wherein the cartridge assembly 60 contains a radially narrower housing groove 61 and a single sealing ring 62 and spring 63. Of course, it is to be understood that while we have illustrated both a single and a dual cartridge assembly that, if desired, more than two sealing rings could be assembled in a common cartridge housing.

In all of the embodiments illustrated, the radial width of the spring member 21 or 63 was substantially the same as the radial width of the channel 37 of the rings. It is to be understood that these members should be dimensioned such that the seal ring is slidable with respect to'the spring rings so that the sealrings may be expanded. However, if desired, a close tolerance can be maintained between the two to aid in effectively sealing against oil flow within the assembly. That is to say, that by maintaining the axially extending legs of the seal rings in contact with the axially extending legs of the spring and by forming the seal ring legs of an axial length sufficient to extend beyond the struck-out portion of the spring which is used to form the spring fingers 44, that an internal axial seal is maintained within the housing preventing flow of oil axially within the cartridge housing inasmuch as the spring ring is always backed against the bight wall of the housing. Altematively, other secondary seals such as quad ring 23 of FIG. 1 may be utilized.

It can therefore be seen from the above that our invention provides a unique cartridge system approach to oil control rings for rotary-piston engines. In the preferred embodiment, the cartridge includes a housing, a pair of independently axially movable seal members, spring means for axially moving the seal members, and means for retaining the seal members and the spring means within the housing in preassembled condition prior to assembly into the engine. Further modifications are concerned with the design of the sealing faces of the sealing members and another modification describes a single sealing member cartridge, including a housing, a sealing member and a spring means. Also disclosed is a novel design for the sealing member and a novel design for the spring member together with illustrations of sealing designs within the cartridge.

Although the teachings of our invention have herein been discussed with reference to specific theories and embodiments and although illustrative means for accomplishing explained results have been described, it is to be understood that these are by way of illustration only and that others may wish to utilize our invention in different designs or applications.

We claim as our invention:

1. An oil control ring assembly for use in rotary piston internal combustion engines, comprising:

a pair of generally U-shaped control rings in side-byside relatively freely axially moveable relation with one ring inside the other ring, each of said control rings being of generally U-shaped cross section with bight portions connecting spaced apart leg portions extending in the same direction on each of the control rings and defining channels opening in the same direction;

each of said control rings having nested therein a complementary respective biasing ring member including spring means thrusting biasingly against the bight portion of the associated control ring and having sealing leg means projecting from the channel beyond the distal ends of the control ring leg portions;

a channel-housing ring within which said control rings are received with said sealing leg means engaging in thrusting sealing relation with bight means of the housing ring;

and a quad sealing ring engaged between said housing bight portion, said leg means and distal ends of contiguous leg portions of said control rings.

2. An oil control ring assembly for use in rotary piston internal combustion engines, comprising:

a 'pair of control rings of generally U-shaped cross section in side-by-side relatively freely axially moveable relation with one ring concentrically inside the other ring, each of said control rings being of generally U-shaped cross section with a bight portions connecting spaced apart leg portion ex tending in the same direction on each of the control rings and defining channels opening in the same direction;

each of said control rings having nested therein a complementary respective biasing ring member including spring means thrusting biasingly against the bight portion of the associated control ring, and having sealing leg means projecting from the channel beyond the distal ends of the control ring leg portions;

a channel-housing ring within which said control rings are received with said sealing leg means engaging in thrusting sealing relation with bight means of the housing ring to prevent leakage through the channel-housing ring; and

means on said housing ring retaining said control rings against escape therefrom.

3. An assembly according to claim 2, including a quad sealing ring engaged between said housing bight portion, said leg means and distal ends of contiguous leg portions of said control rings.

4. An oil control ring assembly for use in rotary piston internal combustion engines, comprising:

an oil control ring of generally U-shape cross section having a bight portion and spaced apart leg portions defining a channel, with a sealing surface on the outer side of said bight portion;

a biasing ring member nested in said channel and having a sealing edge projecting from said channel beyond said leg portions;

a housing within which said control ring and the nested biasing ring member are received;

and biasing spring means thrusting against said bight portion and urging said sealing edge sealing against said housing to prevent leakage through said housing, and means on said housing retaining said control ring against escape therefrom.

5. An assembly according to claim 4, wherein said biasing ring member is of generally U-shape cross section having a bight section in spaced proximity to said bight portion and including a pair of spaced legs both of which provide sealing edges engaging sealing against the housing. said biasing spring means comprising spring projections from said member engaging said bight portion of the control ring and urging both of said leg edges against the housing.

6.- An oil control ring assembly especially useful for rotary piston internal combustion engines, and comprising:

an oil control ring of generally U-shaped cross section having spaced axially extending legs connected by a bight portion providing a sealing'surface and defining a channel opening from the distal ends of said legs;

a biasing ring member slidably nested within said channel and having spring means thrusting in biasing relation against said bight portion and leg means extending from said channel beyond the distal ends of said legs;

a housing of generally U-shaped cross section within which are assembled the nested oil control ring and biasing ring; and

said leg means engaging in thrusting sealing relation with a surface in the bottom of the U-shape of said housing to prevent leakage through the U-shaped housing means on said housing retaining said control ring against escape therefrom.

7. An assembly according to claim 6, wherein said spring means comprise circumferentially spaced spring fingers struck from said biasing ring member.

8. An assembly according to claim 6, said housing including a bight portion connecting axially extending spaced walls defining a channel within which the nested control ring and biasing ring member are received with the sealing surface of the control ring projectable beyond the distal ends of said housing walls, and means on said distal ends of the housing walls for retaining the nested control ring and ring member within the housmg.

9. An assembly according to claim 6, wherein said biasing ring member is of generally U shaped cross section and said leg means comprise a pair of co-extensive legs each of which provides a sealing and thrust edge engaging the housing surface.

10. An assembly according to claim 9, wherein said biasing ring member has a bight portion in spaced proximity relation to said control ring bight portion, and said spring means comprise biasing spring fingers struck from said bight portion of the biasing ring member.

11. An assembly according to claim 10, wherein said biasing spring fingers are struck also partially from said legs of said biasing ring member.

12. An oil control ring cartridge assembly for use in rotary piston internal combustion engines, said cartridge assembly including a housing ring, said housing ring having a radial thickness U-shaped cross section with inner and outer diameter axially extending walls interconnected by a radially extending bight section at one end of the axially extending walls, the axial end opposite the bight section open to an internal channel interior of the walls, an oil control ring in said channel, said oil control ring having a radial thickness of substantially U-shaped cross section and having inner and outer diameter axially extending leg portions interconnected by a radially extending second bight section integral with the leg portions at one axial end thereof and defining therewith a channel opening in the opposite direction from said housing ring channel, said oil control ring received interiorly of the housing channel with the legs of the oil control ring extending toward the bight section of the housing, a spring ring having a radial thickness U-shaped cross section with inner and outer diameter axially extending spring ring walls interconnected by a radially extending bight portion at one axial end of the spring ring walls, said bight portion of the spring ring received interiorly of the channel of the oil control ring and located in spaced proximity to said second bight section, free axial ends of the spring ring walls being in contact with the bight section of the housing, and integral spring projections extending from said bight portion of the spring ring into biasing engagement with said second bight section,

13. An assembly according to claim 12, wherein said spring projections comprise fingers struck from said bight portion of the spring ring.

14. An assembly according to claim 13, wherein said spring fingers are circumferentially spaced and extend in alternate opposite radial directions.

15. An assembly according to claim 14, wherein said spring fingers are struck also partially from said spring ring walls.

16. An oil control ring assembly for use in rotary piston internal combustion engines, the assembly comprising a housing ring, said housing ring having a radial thickness U-shaped cross section with inner and outer diameter axially extending walls interconnected by a radially extending bight section at one end of the axially extending walls, the axial end opposite the bight section open to an internal channel interior of the walls, an oil control seal ring in said channel, spring means entrapped between a portion of said oil control ring and the said bight section, said spring means effective to urge the said oil control ring out of the open end, retaining means on the hou'sing preventing exit of a portion of the oil control ring through said open end, said oil control seal ring having its radial thickness of substantially U-shaped cross section having inner and outer diameter axially extending leg portions interconnected by a radially extending second bight section integral with the leg portions at one axial end thereof and another axial end opposite the second bight section open to a channel intermediate the legs, a sealing surface projecting beyond a portion of said second bight section away from the said channel and out of the open end'of the said housing and the said spring means entrapped between the said second bight section and the said bight section of the housing and having portions thereof positioned interiorly of the said channel of the ring, said spring means comprising a ring-shaped biasing member having a U-shaped radial width cross section with inner and outer diameter concentric legs interconnected at one axial end thereof by a bight section positioned within the channel of the seal ring in spaced proximity relation to said second bight section and the free axial ends of said legs abutting the bight of the housing ring, and spring fingers struck from the material of the bight section of the biasing member and engaging said second bight section to urge the seal ring axially from said housing and said free axial ends w r i ll3i h li9 0 the housing i a 17. An assembly according to claim 16, wherein said spring fingers are spaced circumferentially from one a asing member.

' i w UNIZIED STATES PATENT OFFICE CERTfiIFICATE OF CORRECTION eatm No- 3.822.973 Dated luly 9. 1974 Emvemtmis; He b 'Prasse and Harold E, McCormick It is eertifie-cl that: error appears in the above-identified patent and that said Letters. Patent are hereby corrected as shown below:

On the title page, item [75] for "Harold F. Prasse" read Herbert F. Prasse";

Column 1, line 40; for "illustrated illusire ted" read --illustrated--.

Signed and sealed this 5th day of November 1974.

(SEAL) Attest:

MCCOY M. GIBSON J c. MARSHALL DANN Attesting Officer Commissioner of Patents 

1. An oil control ring assembly for use in rotary piston internal combustion engines, comprising: a pair of generally U-shaped control rings in side-by-side relatively freely axially moveable relation with one ring inside the other ring, each of said control rings being of generally U-shaped cross section with bight portions connecting spaced apart leg portions extending in the same direction on each of the control rings and defining channels opening in the same direction; each of said control rings having nested therein a complementary respective biasing ring member including spring means thrusting biasingly against the bight portion of the associaTed control ring and having sealing leg means projecting from the channel beyond the distal ends of the control ring leg portions; a channel-housing ring within which said control rings are received with said sealing leg means engaging in thrusting sealing relation with bight means of the housing ring; and a quad sealing ring engaged between said housing bight portion, said leg means and distal ends of contiguous leg portions of said control rings.
 2. An oil control ring assembly for use in rotary piston internal combustion engines, comprising: a pair of control rings of generally U-shaped cross section in side-by-side relatively freely axially moveable relation with one ring concentrically inside the other ring, each of said control rings being of generally U-shaped cross section with bight portions connecting spaced apart leg portions extending in the same direction on each of the control rings and defining channels opening in the same direction; each of said control rings having nested therein a complementary respective biasing ring member including spring means thrusting biasingly against the bight portion of the associated control ring and having sealing leg means projecting from the channel beyond the distal ends of the control ring leg portions; a channel-housing ring within which said control rings are received with said sealing leg means engaging in thrusting sealing relation with bight means of the housing ring to prevent leakage through the channel-housing ring; and means on said housing ring retaining said control rings against escape therefrom.
 3. An assembly according to claim 2, including a quad sealing ring engaged between said housing bight portion, said leg means and distal ends of contiguous leg portions of said control rings.
 4. An oil control ring assembly for use in rotary piston internal combustion engines, comprising: an oil control ring of generally U-shape cross section having a bight portion and spaced apart leg portions defining a channel, with a sealing surface on the outer side of said bight portion; a biasing ring member nested in said channel and having a sealing edge projecting from said channel beyond said leg portions; a housing within which said control ring and the nested biasing ring member are received; and biasing spring means thrusting against said bight portion and urging said sealing edge sealing against said housing to prevent leakage through said housing, and means on said housing retaining said control ring against escape therefrom.
 5. An assembly according to claim 4, wherein said biasing ring member is of generally U-shape cross section having a bight section in spaced proximity to said bight portion and including a pair of spaced legs both of which provide sealing edges engaging sealing against the housing, said biasing spring means comprising spring projections from said member engaging said bight portion of the control ring and urging both of said leg edges against the housing.
 6. An oil control ring assembly especially useful for rotary piston internal combustion engines, and comprising: an oil control ring of generally U-shaped cross section having spaced axially extending legs connected by a bight portion providing a sealing surface and defining a channel opening from the distal ends of said legs; and a biasing ring member slidably nested within said channel and having spring means thrusting in biasing relation against said bight portion and leg means extending from said channel beyond the distal ends of said legs; a housing of generally U-shaped cross section within which are assembled the nested oil control ring and biasing ring; and said leg means engaging in thrusting sealing relation with a surface in the bottom of the U-shape of said housing to prevent leakage through the U-shaped housing means on said housing retaining said control ring against escape therefrom.
 7. An assembly according to claim 6, wherein said sPring means comprise circumferentially spaced spring fingers struck from said biasing ring member.
 8. An assembly according to claim 6, said housing including a bight portion connecting axially extending spaced walls defining a channel within which the nested control ring and biasing ring member are received with the sealing surface of the control ring projectable beyond the distal ends of said housing walls, and means on said distal ends of the housing walls for retaining the nested control ring and ring member within the housing.
 9. An assembly according to claim 6, wherein said biasing ring member is of generally U-shaped cross section and said leg means comprise a pair of co-extensive legs each of which provides a sealing and thrust edge engaging the housing surface.
 10. An assembly according to claim 9, wherein said biasing ring member has a bight portion in spaced proximity relation to said control ring bight portion, and said spring means comprise biasing spring fingers struck from said bight portion of the biasing ring member.
 11. An assembly according to claim 10, wherein said biasing spring fingers are struck also partially from said legs of said biasing ring member.
 12. An oil control ring cartridge assembly for use in rotary piston internal combustion engines, said cartridge assembly including a housing ring, said housing ring having a radial thickness U-shaped cross section with inner and outer diameter axially extending walls interconnected by radially extending bight section at one end of the axially extending walls, the axial end opposite the bight section open to an internal channel interior of the walls, an oil control ring in said channel, said oil control ring having a radial thickness of substantially U-shaped cross section and having inner and outer diameter axially extending leg portions interconnected by a radially extending second bight section integral with the leg portions at one axial end thereof and defining therewith a channel opening in the opposite direction from said housing ring channel, said oil control ring received interiorly of the housing channel with the legs of the oil control ring extending toward the bight section of the housing, a spring ring, the spring ring having a radial thickness U-shaped cross section with inner and outer diameter axially extending spring ring walls interconnected by a radially extending bight portion at one axial end of the spring ring walls, said bight portion of the spring ring received interiorly of the channel of the oil control ring and located in spaced proximity to said second bight, free axial ends of the spring ring walls being in contact with the bight section of the housing, and integral spring projections extending from said bight portion of the spring ring into biasing engagement with said second bight portion.
 13. An assembly according to claim 12, wherein said spring projections comprise fingers struck from said bight portion of the spring ring.
 14. An assembly according to claim 13, wherein said spring fingers are circumferentially spaced and extend in alternate opposite radial directions.
 15. An assembly according to claim 14, wherein said spring fingers are struck also partially from said spring ring walls.
 16. An oil control ring assembly for use in rotary piston internal combustion engines, the assembly comprising a housing ring, said housing ring having a radial thickness U-shaped cross section with inner and outer diameter axially extending walls interconnected by a radially extending bight section at one end of the axially extending walls, the axial end opposite the bight section open to an internal channel interior of the walls, an oil control seal ring in said channel, spring means entrapped between a portion of said oil control ring and the said bight section, said spring means effective to urge the said oil control ring out of the open end, retaining means on the housing preventing exit of a portion of the oil control ring through said open end, said oIl control seal ring having its radial thickness of substantially U-shaped cross section having inner and outer diameter axially extending leg portions interconnected by a radially extending second bight section integral with the leg portions at one axial end thereof and another axial end opposite the second bight section open to a channel intermediate the legs, a sealing surface projecting beyond a portion of said second bight section away from the said channel and out of the open end of the said housing and the said spring means entrapped between the said second bight section and the said bight section of the housing and having portions thereof positioned interiorly of the said channel of the ring, said spring means comprising a ring-shaped biasing member having a U-shaped radial width cross section with inner and outer diameter concentric legs interconnected at one axial end thereof by a bight section positioned within the channel of the seal ring in spaced proximity relation to said second bight section and the free axial ends of said legs abutting the bight of the housing, and spring fingers struck from the material of the bight of the biasing member and engaging said second bight section to urge the seal ring axially from said housing and said free axial ends toward said bight section of the housing ring.
 17. An assembly according to claim 16, wherein said spring fingers are spaced circumferentially from one another and extend in alternately opposite radial directions.
 18. An assembly according to claim 17, wherein said spring fingers are struck partly from the legs of said biasing member. 